Tooling method for expanded slit sheet material

ABSTRACT

The present invention discloses a method of producing at least a pair of interlocking adjacent layers of a paper packaging product, the pair of interlocking adjacent layers being formed of a sheet of slit paper having a slit pattern, the slit pattern upon expansion, forming cells that include land regions that are inclined with respect to a plane of an unexpanded sheet. The method comprises slitting the sheet of slit paper with beveled blades that have a first wedge angle on one side of the blades and a second wedge angle on the other side of the blades, wherein the first wedge angle is wider than the second wedge angle to produce slits that upon expansion, produce the lands regions that have angles of inclination in a range for 50 to 85 degrees.

This application claims priority to U.S. Provisional Application No.62/595,473, “TOOLING METHOD FOR EXPANDED SLIT SHEET MATERIAL,” filedDec. 6, 2017, which application is incorporated by reference herein inits entirety.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application references patent applications, U.S. patent applicationSer. No. 14/480,319 filed Sep. 8, 2014 and Ser. No. 15/820,514 filedNov. 22, 2017, the disclosures of which are incorporated by reference intheir entirety, referenced and recited herein as if in full as part ofthe description of the present invention.

BACKGROUND OF THE INVENTION Field of the Invention

This invention provides a method for manufacturing expanded slit sheetmaterial that selectively regulates the production of uniformly openingcells or erratically opened cells.

The Background Art

The expanded slit paper prior art disclosed in U.S. Pat. Nos. 5,538,778,5,667,871, 5,688,578, and 5,782,735, are incorporated by reference intheir entirety, referenced, and recited herein as if in full as part ofthe description of the present invention. The prior art consists oflayering a wrapping comprising a combination of a tissue interleavesheet and an expanded slit sheet for the purposes of cushioning fragileitems for shipment. The prior art also relates to a method of expandingthe slit sheet material using an electrically powered apparatus.

BRIEF SUMMARY OF THE INVENTION

A main object of the present invention is to overcome the shortcomingsof the prior art.

In accordance with some embodiments of the invention, a method ofproducing at least a pair of interlocking adjacent layers of a paperpackaging product, the pair of interlocking adjacent layers being formedof a sheet of slit paper having a slit pattern, the slit pattern uponexpansion, forming cells that include land regions that are inclinedwith respect to a plane of an unexpanded sheet, the method comprisingthe step of: slitting the sheet of slit paper with beveled blades thathave a first wedge angle on one side of the blades and a second wedgeangle on the other side of the blades, wherein the first wedge angle iswider than the second wedge angle to produce slits that upon expansion,produce the lands regions that have angles of inclination in a range for50 to 85 degrees.

In accordance with some embodiments of the invention, the method ofproducing at least a pair of interlocking adjacent layers of a paperpackaging product, the method further comprising the step of: formingthe slit pattern by slitting with the blades against a rotating anvil,the blades having an included angle, wherein the paper is recycledpaper.

In accordance with some embodiments of the invention, the method ofproducing at least a pair of interlocking adjacent layers of a paperpackaging product, wherein the first wedge angle is in the range fromabout 40 to 50 degrees, and the second wedge angle is in the range fromabout 25 to 35 degrees with respect to a center line of the blades.

In accordance with some embodiments of the invention, the method ofproducing at least a pair of interlocking adjacent layers of a paperpackaging product, wherein the first wedge angle is in the range fromabout 40 to 45 degrees, and the second wedge angle is in the range fromabout 30 to 35 degrees with respect to a center line of the blades.

In accordance with some embodiments of the invention, the method ofproducing at least a pair of interlocking adjacent layers of a paperpackaging product, wherein a difference between the first wedge angleand the second wedge angle is at least 10 degrees.

In accordance with some embodiments of the invention, the method ofproducing at least a pair of interlocking adjacent layers of a paperpackaging product, wherein the second wedge angle is at least 25degrees.

In accordance with some embodiments of the invention, an apparatus forat least a pair of interlocking adjacent layers of a paper packagingproduct, the pair of interlocking adjacent layers being formed of asheet of slit paper, the sheet of slit paper having a slit pattern, theslit pattern upon expansion, forming cells that include land regionsthat are inclined with respect to a plane of an unexpanded sheet, theapparatus comprising: a first means for slitting the sheet of slit paperwith beveled blades that have a first wedge angle on one side of theblades and a second wedge angle on the other side of the blades, whereinthe first wedge angle is wider than the second wedge angle to produceslits that upon expansion, produce the lands regions that have angles ofinclination in a range for 50 to 85 degrees.

In accordance with some embodiments of the invention, the apparatus forat least a pair of interlocking adjacent layers of a paper packagingproduct, the apparatus further comprising: a second means for formingthe slit pattern by slitting with the blades against a rotating anvil,the blades having an included angle, wherein the paper is recycledpaper.

In accordance with some embodiments of the invention, the apparatus forat least a pair of interlocking adjacent layers of a paper packagingproduct, wherein the first wedge angle is in the range from about 40 to50 degrees, and the second wedge angle is in the range from about 25 to35 degrees with respect to a center line of the blades.

In accordance with some embodiments of the invention, the apparatus forat least a pair of interlocking adjacent layers of a paper packagingproduct, wherein the first wedge angle is in the range from about 40 to45 degrees, and the second wedge angle is in the range from about 30 to35 degrees with respect to a center line of the blades.

In accordance with some embodiments of the invention, the apparatus forat least a pair of interlocking adjacent layers of a paper packagingproduct, wherein a difference between the first wedge angle and thesecond wedge angle is at least 10 degrees.

In accordance with some embodiments of the invention, the apparatus forat least a pair of interlocking adjacent layers of a paper packagingproduct according to claim 7, wherein the second wedge angle is at least25 degrees.

BRIEF DESCRIPTION OF THE DRAWINGS

The preferred embodiments of the present invention will be describedwith reference to the accompanying drawings, in which:

FIG. 1 is a line drawing of a center bevel cutting blade.

FIG. 2 is side view of the center bevel cutting blade oriented toproduce uniformly opening cells.

FIG. 3 is a side view of the center bevel cutting blade oriented toproduce erratically opening cells.

FIG. 4 is a top view of one of the layers of unexpanded slit sheet papermaterial.

FIG. 5 is a top perspective view of one layer of expanded sheetmaterial.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

While the present invention may be embodied in many different forms, theillustrative embodiments are described herein with the understandingthat the present disclosure is to be considered as providing examples ofthe principles of the invention and that such examples are not intendedto limit the invention to preferred embodiments described herein and/orillustrated herein.

Definitions

Where the definition of terms departs from the commonly used meaning ofthe term, applicant intends to utilize the definitions provided below,unless specifically indicated otherwise.

For the purposes of the present invention, the term “slit sheetmaterial” refers to the use of offset rows of slits that form ahexagonal, or the like, three dimensional paper material that isflexible and can form to the shape of an item needing wrapping.

For the purposes of the present invention, the term “cell” means thehollow three dimensional shapes that are created when the slit sheetmaterial is expanded longitudinally.

For the purposes of the present invention, the term “lead wall” meansthe part of the cell that is the full height of the hexagonal shapecreated from the expansion of the slit sheet material.

For the purposes of the present invention, the term “angle ofinclination” means the angle that the land areas of cells form withrespect to the plane of the unexpanded slit sheets, wherein the cellshave land areas that are inclined relative to unexpanded sheets, andwherein the angle of inclination of one of the adjacent expanded sheetsis the mirror image of the angle of inclination of the other expandedsheet.

For the purposes of the present invention, the term “connecting wall”means the part of the cell that is half the height of the cell createdfrom the expansion of the slit sheet material.

For the purposes of the present invention, the term “cell size” meansthe open space dimension created when expanding the slit sheet material.

For the purposes of the present invention, the term “slit row spacing”means the distance between the rows of slit and un-slit patterns withinthe slit sheet material.

For the purposes of the present invention, the term “Kraft paper” meansthe industry name of paper that is measured in weight for every threethousand square feet of material. Thus the weight of 50# Kraft Paperwould be the weight of 3000 square feet of paper.

For the purposes of the present invention, the term “basis weight” meansthe specification relating to paper that measures the weight of acertain square foot area of paper. Thus the basis weight of 3000 squarefeet of Kraft Paper weighing 50 pounds equals a 50# basis weight. Thebasis weight of Tissue paper is based on 2,880 square feet.

For the purposes of the present invention, the term “recycled paper”means material that is substantially made from recycled paper in the 90%range or more and is paper that has been returned to the manufacturingprocess, having once or more been made into a paper product, and remadeinto a paper sheet.

For the purposes of the present invention, the term “paper fibers” arethe individual component of paper that makes up a paper sheet.

For the purposes of the present invention, the term “nesting” means thegrouping of cells onto or into one other such that an upper slit sheetmaterial cell can fit within the lower slit sheet material cell to thepoint at which the thickness gain is not substantial.

For the purposes of the present invention, the term “interlocking” meansthe grouping of cells onto or into one another is such that an upperslit sheet material cell can nest within the lower slit sheet materialcell only to the point at which the average thickness gain of two layersis no less than 70% of the thickness of both layers of a two layer pairand preferably, no less than 80% of the thickness of both layers of atwo layer pair. For example, if each layer is 0.5 inches thick, then theaverage thickness would be no less than 0.7 inches and preferably noless than 0.8 inches.

For the purposes of the present invention, the term “adjacent” meansthat two layers are immediately adjoining, that is, one layer overlaysthe other without intervening space and are touching. Layers that nestor interlock to any degree and having no intervening layers, areaccordingly, in contact with each other and therefore adjacent.

For the purposes of the present invention, the term “pattern of cells ofexpanded sheets” means the cell shape configurations such as hexagonalor oval, and cell dimensions such as leg length or width. The term“pattern” means physical characteristics and dimensions and is notinclusive of decorative or ornamental features of the design of apattern.

For the purposes of the present invention, the term “average thickness”is employed to indicate that since some nesting may be present in layersof sheet that are within the definition of “interlocking” as employedhere, the thickness of two adjacent layers can vary. Average thicknessis measured as the sum of the thicknesses measured at a plurality oflinear intervals, divided by the number of intervals in the plurality oflinear intervals. Thus, if thickness measurements are taken every inchover a length of two feet, then the sum of the measurements divided by24 equals the average thickness.

For the purposes of the present invention, the term “interlockingadjacent layers” means that layers are nested to an extent that thecontact between adjacent layers is sufficient to resist contraction ofexpanded sheets. When two layers are interlocked, the contraction fromexpanded to unexpanded due to the paper's memory is restricted becauseone layer is pulling in a first direction and the second layer ispulling in the opposite direction. The degree of nesting depends uponthe rigidity of the paper of each of the two layers, and preferablyprovides no more than a 10% overlap (nesting) of the layers such thatthe thickness of the two layers is no less than 90% of the sum of thethickness of each layer.

For the purposes of the present invention, the phrase “paper width afterexpansion” means the width of the sheet of paper after expansion of theslit paper sheet. The decrease of the width of the sheet of paper afterexpansion is referred to as “necking down”. The “percent of neckingdown” is the percent decrease in paper width after expansion. Thus, a 25inch width sheet which necks down to 20 inches would be necked down 20%.

For the purposes of the present invention, the phrase “paper widthdifferential” means the difference in width of two adjacent layers ofslip paper sheets. Since different slit patterns will yield differentamounts of necking down, the paper width differential prior to theexpansion step must be sufficient to yield little or no paper widthdifferential after the expansion step. It should be understood that thesheets of expanded paper can be trimmed down to negate any paper widthdifferential post expansion. However, this would constitute a waste ofpaper and require an additional step or steps, and accordingly, it ispreferable to negate any paper width differential by determining apre-expansion paper width differential that achieves, in combinationwith the slit patterns of each of two adjacent sheets, a substantiallyidentical paper widths post expansion.

For the purposes of the present invention, the term “Operator” means theperson that operates the machinery that automatically expands the slitsheet material that dispenses the product towards the operator.

For the purposes of the present invention, the term “switch back” meansthe reversal of the angle of inclination of the land at some point orpoints along the length of a sheet of expanded slit sheet material. Areversal of the angle of inclination from +60° to −60° (60° to 120°)constitutes a switch back.

For the purposes of the present invention, the term “wedge effect” meansthe cutting of a slit to form a slit having a substantially greaterangled cut along one edge of the slit than the other edge of the slit.

For the purposes of the present invention, the term “soft paper” meansthe particular grade of paper used for absorbing purposes, such astissues, drying cloths, paper toweling, napkins and handkerchiefs. Whilethese paper products, unlike their woven fabric counterparts, aretypically intended for disposable use, in the present invention softpaper is employed for its soft feel, smooth structure, and good strengthin both dry and wet states.

For the purposes of the present invention, the term “erraticallyopening” as employed herein, means the random, disorderly, disordered,chaotic, scrambled opening of cells of slit paper sheets duringexpansion of the paper, such that cells of adjacent layers of expandedsheet interlock rather than nest.

DETAILED DESCRIPTION

The new art provides a stronger and longer life solution formanufacturing slit sheet expanded material described in pending U.S.patent application Ser. No. 14/480,319. The disclosures of U.S. patentapplication Ser. No. 14/480,319 filed Sep. 8, 2014, and Ser. No.15/001,168 filed Jan. 19, 2016, and Ser. No. 15/820,514 filed Nov. 22,2017 are incorporated herein by reference in their entirety, and recitedherein as if in full as part of the description of the presentinvention.

Slit Sheet Materials

For the purposes of the present invention, the descriptions of the paperand slit patterns within the embodiment of U.S. Pat. No. 5,667,871 canbe used within this application. The material can be as described in the'871 patent, except that the two differently sized slit patterns areemployed in the present invention, rather than just the one pattern ofthe '871 patent. These two slit patterns substantially negate thenesting problem associated with the prior art U.S. Pat. No. 5,667,871.

Further information relating to the paper which can be used in thepresent invention, sit patterns, and the expansion process is found inU.S. Pat. Nos. 5,538,778, 5,667,871, 5,688,578, and 5,782,735, thedisclosures of which are incorporated by reference herein, as thoughrecited in full.

Each slit pattern will require varying paper strength and thickness toperfect its crush strength and ease of stretching within the automatedexpander.

The slit pattern dimensions set forth below are one example of thecomposite products from the two or more varying slit sheet materials.There are a number of slit sheet variations that will work to inhibitnesting and the specific dimensions and shapes created below should notlimit the patterns that can be used to make the new art. The criticalfeature is that the slit patterns of adjacent layers differ in slitlength, spacing between slits in a row, and/or the spacing between rowsof slits.

The paper used to manufacture the slit sheet material is preferred to berecycled and is in the range of 30-80 pounds in basis weight dependentupon the cell size of the slit sheet expanded material. Virgin paper haslonger fibers and will produce a firmer product with equivalent basisweight as recycled paper. Again, depending on the cushioning requiredone may use a 30 pound recycled paper to obtain a very soft cushion andalternating between recycled and virgin as the paper weight goes up finetunes the cushioning effect. Additionally, a soft cushion recycled papercan be used for one sheet of the pair of sheets and the other can be ahigher weight recycled paper or virgin paper. Kraft paper ismanufactured according to the Tappi T-410 (standard of 3,000 Square feetof material per basis weight. As an example a Kraft paper with a basisweight of 40 means that 3,000 square feet will weigh 40 pounds.Interestingly the paper is about 0.004 inches thick but this can varybased on crushing methods to produce different surfaces.

In the case of a cushioning product made from Kraft paper the idealpaper weight, depending on the cushioning requirements is 30 to 90pounds.

It is preferred to use the slit pattern that is approximatelythree-to-one in size between the length of the slit portion and theun-slit portion of the slit sheet material. In this instance a ½″ slitportion followed by a 3/16″ un-slit portion is a preferred pattern inthe first row. Each row is ⅛″ apart and bisects or is transverse to thedirection of manufacturing the slit sheet material. Each slit patternrow below is offset to the above pattern such that the slit portionbisects the unslit pattern of the upper row and so forth. Thisalternating pattern enables the paper to be expanded in to the web ofhexagonal, diamond, square, or round shaped three dimensional cells thatare created dependent upon the specific slit pattern. A hexagonalpattern is created with the approximate three-to-one slit to unslitlengths. It has been established that the hexagonal shape is thestrongest of all the cell shapes and therefore is the preferredembodiment to the new art. There are exceptions when a softer cushioningmaterial is required where one of the slit sheet materials is ahexagonal layer with the adjoining layer slit sheet designed to be asquare. In this instance the preferred embodiment is for both layers tosubstantially create hexagonal cells.

The second layer of slit sheet material will be of the same threedimensional thickness. The thickness can be created from the spacing ofthe rows. In this instance the spacing is ⅛″ thus creating ¼″ longcells. Because these cells can only rotate short of 90 degrees toward avertical orientation, the total height is approximately 3/16″ overall.The lead wall of the cell is the portion of the cell that makes up thefull depth of the slit sheet when expanded. There are two lead wallscreated no matter what shape the cells create or slit pattern used.These two lead walls face the direction of manufacture and the surfacearea is made up of the un-slit area within the row and the space betweenthe rows times 2. The depth of the lead wall can also be described asthe unslit space between every other set of rows or between the firstand third rows.

The overall height of the expanded slit sheet material can also bedescribed as a series of rows such that the first row of slits atposition “O” is followed by its offset un-slit portion of the rowunderneath at position ⅛″ below and not until the third row appears andthe offset again places a slit at position ¼″, thereby creating a totalheight of ¼″ for the lead walls of the hexagonal cell.

FIG. 4 is the top view of one layer of the slit paper prior to expansionwith 100 being the width of the slit and 101 being width of the unslitdimension. 102 is the distance between the rows.

FIG. 5 is the top view of one layer of the slit sheet expanded to itsthree dimensional form with 800 being the open cell area created by theexpansion, 801 being the lead wall or land created, and 802 being theconnecting leg. It is noted that the terms lead wall and land are usedinterchangeably to indicate the region 801.

EXAMPLES

The first slit sheet pattern creates a ¼″ tall lead wall with eachhexagonal side approximately being 3/16″ long. The second slit sheetpattern is also 1/″ tall by using the ⅛″ row spacing. The legs of thecell are approximately 10 to 30% less or more to create an interlockingcomposite product. In this case the preferred size would be 0.4slit×0.15″ unslit creating a cell that will be 20% smaller than thefirst slit sheet pattern.

The second expanded slit sheet pattern creates a cell that easily couldfit inside the first expanded slit sheet material but is inhibited bythe increase in quantity of the smaller cell size causing 1.2 cellstrying to fit within one cell of the first expanded sheet which, isimpossible.

In order for the operator to receive both slit sheet expanded materialsat the same speed a special expander is required. The first expandedsheet layer expands from 1″ to approximately 2⅛″ inches depending uponpaper strength and thickness. In the present invention the 80 poundbasis weight paper expands to the 2⅛″ inches for the ½″× 3/16″ firstslit sheet layer. This is an approximately 213% increase in the lengthof the slit sheet material and the expander will need create this exactexpansion property for the first layer.

The second layer will be twenty percent smaller in size and thereforewill expand 193% in length. Therefore the second expansion rollerswithin the expander machinery will have a reduced expansion ratio toaccommodate this smaller amount of expansion. This reduced expansionratio would therefore automatically reduce the smaller secondary weblayer speed exiting from the expander. To maintain the same exilingspeed for both layers the back rollers that set the overall exit speedwill have to be adjusted to 20% faster for the second layer.

Additionally, slight variations in cell size, of 5 to 10%, can be openedwith the same Velcro to rubber roller ratio as the larger cell size dueto the slipping effect of the Velcro rollers. As the cell size grows theeffect is minimized and either a larger cell is not opened fully formaximum benefit or a small cell shows tears or complete tearing of theslit sheet material.

With only a slight cell size variation the paper width does not have tobe exact such that if one web is slightly wider by no more than 5 to 10%then the efficiency of wrapping is maintained. This would make theloading of the expander easier as the upper web could be the lower weband visa-versa and the only difference would be the cell size on theupper web may change from smaller to larger or visa-versa.

Two expanded slit sheets or layers of a single sheet with a tissueseparator have a thickness that is theoretically 3/16″+ 3/16″= 6/16″(0.375″), but has been measured to be 11/32″ or 0.344″. By way ofcontrast two interlocked layers of expanded sheet material, inaccordance with the present invention measured at 3/16″+ 3/16″ toproduce a thickness of 5/16″ or 0.3125″. The loss of thickness of thetwo interlocked layers of expanded slit paper represents the amount ofinterlocking of the two adjacent, overlaid sheets of expanded slit paperof the present invention.

While this represents a 9% loss of thickness, it has been found that inuse, the expanded slit sheets with a tissue separator tends to flattendue to the cells having limited rigidity under a load and has a tendencyto retract. By way of contrast, the interlocking design of the presentinvention, as compared to the tissue separated design of the prior art,is more resistant to deformation under load, more resilient, and resistsretraction. It has been found that in use, the design of the presentinvention produces a wrap that is thicker than the tissue separateddesign of the prior art, presumably because of its ability to retain itsthickness, in contrast to the tissue separator configuration. The tissueseparated design of the prior art, has been found to generally retainless than 75% of its expanded length, whereas the crisscross pattern ofthe present invention tends to retain greater than 75% of its fullyexpanded length.

In another 12 layers with zero nesting has a thickness of 2.25″, wereeach expanded sheet layer has a thickness of 0.1875″ (0.1875×12=2.25″.example 12 layers have a thickness of about 2″, representing a loss ofthickness of about 11%. Thus, preferably, the nesting is limited to 10to 20% and most preferably it is limited to 9 to 15%.

Blade Design

The use of a center bevel sharpened blade is well known for flatbed diecutting, where the downward pressure is absolutely vertical. The bladeis supported on both sides of the sharpened edge versus a side bevelsharpening that produces a straight side and a wedge side. In the rotarydie cutting process of the present invention, the side bevel bladerotates to the vertical and therefore, there is a time where it isimpacting the paper prior to absolutely vertical. This adds alongitudinal pressure that can damage the blade. It has now been foundthat it is best if there is a bevel on both sides of the blade in theformation of expanded slit paper sheets.

However, the center bevel design limits the control of the celldirection as both sides of the blade are identical in wedge effect andtherefore, can create inconsistent/erratic cell openings but on a lesscontrolled basis. Previously, the center bevel blade of equal angles, asillustrated in FIG. 16 of U.S. patent application Ser. No. 14/480,319,blade 1600, created erratically opened cells in an uncontrolled pattern.The side bevel blades 1602 and 1604 of FIG. 16 had a short blade lifewhen used in the formation of uniformly opening cells or erraticallyopening cells.

In accordance with some preferred embodiments of the present invention,there is a substantial improvement of the useful life of the slitforming blades that are employed to produce either uniformly orerratically opened cells in a controlled manner. This is achieved byconstructing a wedge angle that is different on each side of the blade.The wider wedge will have the greater effect on the paper and thereforewill open the cell in the desired direction dependent upon whichdirection it is facing. This design can create erratically opened cellson a row by row basis by alternating the forward or backward directionof the most pronounced wedge side of the blade and conversely, theblades can be oriented to always have the greatest wedge in only onedirection to produce uniformly opened cells.

When the blades are oriented such that the rows of wider wedge all faceforward, uniformly opened cells are created. If the blades are orientedsuch that the first row of blades face the wider wedge forward and thesecond row of blades face the wider wedge backward with each subsequentrow alternating back and forth, then the cells are caused to openerratically. The first-row wedge effect will force the cells to openforward while the second row will force the cells to open backward andso on. Similarly, a random blade orientation can be used to produce arandom, chaotic opening of cells.

In both instances, the instant art center bevel design is engineered todirect the cells where previously it was only feasible with a side bevelsharpened blade, as taught in U.S. application Ser. No. 14/480,319 filedSep. 8, 2014.

FIG. 1 is a side view of a single blade of the new art, where blade 100has a first wedge side 101 that has been sharpened to a specific acuteangle 105 as it relates to the imaginary center line 107. Wedge side 102is then sharpened to create a wider wedge angle 106 relative to theimaginary center line 107. Flat edge 103 is integrally joined to thetool and the rest of the cutting knives. Paper 104 is cut and forcedinto a wedge such that the pronounced wedge effect is on blade side 102.

FIG. 2 is a side view of the uniform blade configuration, where blades100 have their respective acute wedge angles 105 facing to the rightwhile the wider angle is facing to the left. This creates a consistentwedge effect onto paper 104 such that the paper will open uniformly.

FIG. 3 is a side view of the erratic blade configuration, where blades100 have their respective wider wedge angles 106 facing each other andacute wedge angles 105 facing also facing each other. This bladeconfiguration creates an alternating cell opening pattern, where eachrow desires to opening in the opposite direction of the previousdirection.

Angle 106 is preferably in the range from about 40-50°, and angle 105 ispreferably in the range from about 25-35° with respect to the centerline 107 of blade 103. More preferably, angle 106 is in the range fromabout 40-45°, and angle 105 is in the range from 30-35°. Preferably,angles 105 and 106 differ by at least 10° and more preferably differ byat least 10° and most preferably, by at least 15°. Preferably, angle 105is at least 25°.

All references, including publications, patent applications, andpatents, cited herein are hereby incorporated by reference to the sameextent as if each reference were individually and specifically indicatedto be incorporated by reference and were set forth in its entiretyherein.

While illustrative embodiments of the invention have been describedherein, the present invention is not limited to the various preferredembodiments described herein, but includes any and all embodimentshaving equivalent elements, modifications, omissions, combinations(e.g., of aspects across various embodiments), adaptations and/oralterations as would be appreciated by those in the art based on thepresent disclosure. The limitations in the claims are to be interpretedbroadly based on the language employed in the claims and not limited toexamples described in the present specification or during theprosecution of the application, which examples are to be construed asnon-exclusive. For example, in the present disclosure, the term“preferably” is non-exclusive and means “preferably, but not limitedto”. In this disclosure and during the prosecution of this application,means-plus function or step plus-function limitations will only beemployed where for a specific claim limitation all of the followingconditions are present in that limitation; a) “means for” or “step for”is expressly recited; b) a corresponding function is expressly recited;and c) structure, material or acts that support that structure are notrecited. In this disclosure and during the prosecution of thisapplication, the terminology “present invention” or “invention” may beused as a reference to one or more aspect within the present disclosure.The language “present invention” or “invention” should not be improperlyinterpreted as an identification of criticality, should not beimproperly interpreted as applying across all aspects or embodiments(Le., it should be understood that the present invention has a number ofaspects and embodiments), and should not be improperly interpreted aslimiting the scope of the application or claims. In this disclosure andduring the prosecution of this application, the terminology “embodiment”can be used to describe any aspect, feature, process or step, anycombination thereof, and/or any portion thereof, etc. In some examples,various embodiments may include overlapping features. In thisdisclosure, the following abbreviated terminology may be employed:“e.g.” which means “for example”.

The use of the terms “a” and “an” and “the” and similar references inthe context of this disclosure (especially in the context of thefollowing claims) are to be construed to cover both the singular and theplural, unless otherwise indicated herein or clearly contradicted bycontext. All methods described herein can be performed in any suitableorder unless otherwise indicated herein or otherwise clearlycontradicted by context. The use of any and all examples, or exemplarylanguage (e.g., such as, preferred, preferably) provided herein, isintended merely to further illustrate the content of the disclosure anddoes not pose a limitation on the scope of the claims. No language inthe specification should be construed as indicating any non-claimedelement as essential to the practice of the present disclosure.

Multiple embodiments are described herein, including the best mode knownto the inventors for practicing the claimed invention. Of these,variations of the disclosed embodiments will become apparent to those ofordinary skill in the art upon reading the foregoing disclosure. Theinventors expect skilled artisans to employ such variations asappropriate (e.g., altering or combining features or embodiments), andthe inventors intend for the invention to be practiced otherwise than asspecifically described herein.

Accordingly, this invention includes all modifications and equivalentsof the subject matter recited in the claims appended hereto as permittedby applicable law. Moreover, any combination of the above describedelements in all possible variations thereof is encompassed by theinvention unless otherwise indicated herein or otherwise clearlycontradicted by context.

The use of individual numerical values is stated as approximations asthough the values were preceded by the word “about”, “substantially”, or“approximately.” Similarly, the numerical values in the various rangesspecified in this application, unless expressly indicated otherwise, arestated as approximations as though the minimum and maximum values withinthe stated ranges were both preceded by the word “about”,“substantially”, or “approximately.” In this manner, variations aboveand below the stated ranges can be used to achieve substantially thesame results as values within the ranges. As used herein, the terms“about”, “substantially”, and “approximately” when referring to anumerical value shall have their plain and ordinary meanings to a personof ordinary skill in the art to which the disclosed subject matter ismost closely related or the art relevant to the range or element atissue. The amount of broadening from the strict numerical boundarydepends upon many factors. For example, some of the factors which may beconsidered include the criticality of the element and/or the effect agiven amount of variation will have on the performance of the claimedsubject matter, as well as other considerations known to those of skillin the art.

As used herein, the use of differing amounts of significant digits fordifferent numerical values is not meant to limit how the use of thewords “about”, “substantially”, or “approximately” will serve to broadena particular numerical value or range. Thus, as a general matter,“about”, “substantially”, or “approximately” broaden the numericalvalue.

Also, the disclosure of ranges is intended as a continuous rangeincluding every value between the minimum and maximum values plus thebroadening of the range afforded by the use of the term “about”,“substantially”, or “approximately”. Thus, recitations of ranges ofvalues herein are merely intended to serve as a shorthand method ofreferring individually to each separate value falling within the range,unless otherwise indicated herein, and each separate value isincorporated into the specification as if it were individually recitedherein.

To the extent that determining a given amount of variation of some thefactors such as the criticality of the slit patterns, paper widthdifferential pre- and post-expansion, paper weights and type, as well asother considerations known to those of skill in the art to which thedisclosed subject matter is most closely related or the art relevant tothe range or element at issue will have on the performance of theclaimed subject matter, is not considered to be within the ability ofone of ordinary skill in the art, or is not explicitly stated in theclaims, then the terms “about”, “substantially”, and “approximately”should be understood to mean the numerical value, plus or minus 15%.

It is to be understood that any ranges, ratios and ranges of ratios thatcan be formed by, or derived from, any of the data disclosed hereinrepresent further embodiments of the present disclosure and are includedas part of the disclosure as though they were explicitly set forth. Thisincludes ranges that can be formed that do or do not include a finiteupper and/or lower boundary. Accordingly, a person of ordinary skill inthe art most closely related to a particular range, ratio or range ofratios will appreciate that such values are unambiguously derivable fromthe data presented herein.

The invention claimed is:
 1. A method of producing a paper packagingproduct including a sheet of slit paper having a slit pattern, the slitpattern upon expansion forming cells that include land regions that areinclined with respect to a plane of an unexpanded sheet, the methodcomprising the steps of: slitting the sheet of slit paper, expanding thesheet of slit paper with said slits producing land regions that haveangles of inclination in a range from 50 to 85 degrees from the plane ofthe unexpanded sheet, with said land regions alternating on a row by rowbasis in forward and backward directions such that the slit pattern uponexpansion includes an alternating cell opening pattern wherein each rowopens in an opposite direction from an adjacent row.
 2. The methodaccording to claim 1, further comprising the step of: forming the slitpattern by slitting with blades, and wherein the paper is recycledpaper.
 3. The method according to claim 2, wherein the blades have afirst wedge angle on one side of the blades and a second wedge angle onthe other side of the blades, wherein the first wedge angle is in therange from about 40 to 50 degrees, and the second wedge angle is in therange from about 25 to 35 degrees with respect to a center line of theblades.
 4. The method according to claim, wherein wherein said sheet ofslit paper is configured to form said land regions alternating on a rowby row basis in forward and backward directions and said alternatingcell opening pattern wherein each row opens in an opposite directionfrom an adjacent row by an operator expanding the sheet of slit paperwith an expander.
 5. The method according to claim 1, wherein said cellpattern includes an array of hexagonal cells.
 6. The method according toclaim 2, wherein said cell pattern includes an array of hexagonal cells.7. The method according to claim 1, wherein said paper packaging productcomprises two adjacent layers that nest less than 20%.
 8. The methodaccording to claim 7, wherein said paper packaging product comprises twoadjacent layers that nest less than 10%.
 9. The method according toclaim 7, wherein a thickness of two adjacent layers is no less than 70%of twice the thickness of a single layer.
 10. The method according toclaim 7, wherein a thickness of two adjacent layers is no less than 80%of twice the thickness of a single layer.
 11. An apparatus for producinga paper packaging product including a sheet of slit paper, the sheet ofslit paper having a slit pattern, the slit pattern upon expansionforming cells that include land regions that are inclined with respectto a plane of an unexpanded sheet, the apparatus comprising: a slitterthat slits the sheet of slit paper with a plurality of blades, whichproduce slits that upon expansion, produce land regions that have anglesof inclination in a range from 50 to 85 degrees from the plane of theunexpanded sheet, with said land regions alternating on a row by rowbasis in forward and backward directions such that the slit pattern uponexpansion includes an alternating cell opening pattern wherein each rowopens in an opposite direction from an adjacent row.
 12. The apparatusaccording to claim 11, further comprising: wherein the paper is recycledpaper.
 13. The apparatus according to claim 11, wherein the blades havea first wedge angle on one side of the blades and a second wedge angleon the other side of the blades, wherein the first wedge angle is in therange from about 40 to 50 degrees, and the second wedge angle is in therange from about 25 to 35 degrees with respect to a center line of theblades.
 14. The apparatus according to claim 11, wherein said sheet ofslit paper is configured to form said land regions alternating on a rowby row basis in forward and backward directions and said alternatingcell opening pattern wherein each row opens in an opposite directionfrom an adjacent row by an operator expanding the sheet of slit paperwith an expander.
 15. The apparatus according to claim 11, wherein saidcell pattern includes an array of hexagonal cells.
 16. The apparatusaccording to claim 11, wherein said cell pattern includes an array ofhexagonal cells.
 17. The apparatus according to claim 11, wherein saidpaper packaging product comprises two adjacent layers that nest lessthan 20%.
 18. The apparatus for at least a pair of interlocking adjacentlayers of a paper packaging product according to claim 11, wherein saidpaper packaging product comprises two adjacent layers that nest lessthan 10%.
 19. The apparatus according to claim 11, wherein a thicknessof two adjacent layers is no less than 70% of twice the thickness of asingle layer.
 20. The apparatus according to claim 11, wherein athickness of two adjacent layers is no less than 80% of twice thethickness of a single layer.
 21. A paper packaging product produced bythe method of claim 1, comprising: a sheet of slit paper having a slitpattern, the slit pattern upon expansion forming cells that include landregions that are inclined with respect to a plane of an unexpandedsheet; the sheet of slit paper being configured such that expanding thesheet of slit paper with said slits produces land regions that haveangles of inclination in a range from 50 to 85 degrees from the plane ofthe unexpanded sheet, with said land regions alternating on a row by rowbasis in forward and backward directions such that the slit pattern uponexpansion includes an alternating cell opening pattern wherein each rowopens in an opposite direction from an adjacent row.
 22. A paperpackaging product, comprising: a sheet of slit paper having a slitpattern, the slit pattern upon expansion forming cells that include landregions that are inclined with respect to a plane of an unexpandedsheet; the sheet of slit paper being configured such that expanding thesheet of slit paper with said slits produces land regions that haveangles of inclination in a range from 50 to 85 degrees from the plane ofthe unexpanded sheet, with said land regions alternating on a row by rowbasis in forward and backward directions such that the slit pattern uponexpansion includes an alternating cell opening pattern wherein each rowopens in an opposite direction from an adjacent row.